A Biomimetic, 4.5 $mu$W, 120+ dB, Log-Domain Cochlea Channel With AGC
Katsiamis, A.G.
Drakakis, E.M.
Lyon, R.F.
Dept. of Bioeng., Imperial Coll. London, London;
This paper appears in: Solid-State Circuits, IEEE Journal of
Publication Date: March 2009
Volume: 44,
Issue: 3
On page(s): 1006-1022
ISSN: 0018-9200
INSPEC Accession Number: 10477191
Digital Object Identifier: 10.1109/JSSC.2008.2011039
Current Version Published: 2009-02-24
Abstract
This paper deals with the design and performance evaluation of a new analog CMOS cochlea channel of increased biorealism. The design implements a recently proposed transfer function, namely the One-Zero Gammatone filter (or OZGF), which provides a robust foundation for modeling a variety of auditory data such as realistic passband asymmetry, linear low-frequency tail and level-dependent gain. Moreover, the OZGF is attractive because it can be implemented efficiently in any technological medium-analog or digital-using standard building blocks. The channel was synthesized using novel, low-power, class-AB, log-domain, biquadratic filters employing MOS transistors operating in their weak inversion regime. Furthermore, the paper details the design of a new low-power automatic gain control circuit that adapts the gain of the channel according to the input signal strength, thereby extending significantly its input dynamic range. We evaluate the performance of a fourth-order OZGF channel (equivalent to an 8th-order cascaded filter structure) through both detailed simulations and measurements from a fabricated chip using the commercially available 0.35 mum AMS CMOS process. The whole system is tuned at 3 kHz, dissipates a mere 4.46 muW of static power, accommodates 124 dB (at < 5% THD) of input dynamic range at the center frequency and is set to provide up to 70 dB of amplification for small signals.
Index
Terms
Available to subscribers and IEEE members.
References
Available to subscribers and IEEE members.
Citing Documents
Available to subscribers and IEEE members.
Cart
